The present invention relates in general to the domain of semiconductor films based on silicon technology. It concerns, more particularly, a method for producing silicon junctions, doped or not, which can be used, for example, in solar cells. It also concerns any other semi-conducting devices obtained by such a method.
Amorphous or microcrystalline silicon solar cells are made of multilayer systems where semiconducting material with certain electronical and physical properties is deposited, layer by layer, on a substrate.
The n-layers and p-layers are doped with other elements to achieve desired properties, such as electrical conductivity. More precisely:                p-doped layers have a surplus of positive charge carriers,        n-doped layers have a surplus of negative charge carriers, and        i layers are intrinsic.        
Generally, boron is used as the doping agent of the p-layers and phosphor as the doping agent of the n-layers.
Silicon solar cells manufacturers use either single-chamber or multi-chamber reactors to produce commercial photovoltaic (PV) modules. Plasma deposition of silicon solar cells in a single-chamber reactor leads to considerable simplifications and reduced costs as compared to multi-chamber processes.
However, in a single chamber deposition process of a p-i-n solar cell, for example, the subsequent deposition of the i-layer on the p-layer may cause boron recycling from the reactor walls and from the deposited p-layer. As a result, boron will contaminate the i-layer at the critical p-i interface and thereby weaken the strength of the electrical field in the i-layer close to p-i interface. This provokes a less efficient carrier separation just in this zone and leads to a reduced collection efficiency in the solar cell and thereby to a deterioration of the cell performance.
For that reason, most silicon p-i-n solar cells modules are, at present, deposited using multi-chamber reactors. Boron cross-contamination by recycling is avoided by simply depositing the p-layer and the i-layer in different chambers. However, the higher investment in multi-chamber systems equipment becomes a drawback particularly in the field of solar cells where costs are a major issue.
Similar problems exist with n-i-p solar cells in which phosphor used to dope the n-layer contaminates the i-layer at the critical n-i interface.
Thus, an interesting solution would be to combine a low cost-single chamber reactor with a process scheme able to suppress the boron or phosphor cross-contamination.
Different treatments have been tested with encouraging results, but they still leave open the question of the light-induced degradation of these solar cells, they use expensive gases, they have long treatment durations or are incompatible with large area deposition in industrial reactors.